git init with template dir

git init with template dir

[Alex Cornejo]

I was surprised to see that when using git-init, if the template folder
is itself a symlink, then the contents of the template is NOT copied to
the resulting git repository, but instead each individual file is
symlinked.

For my particular use case, this is undesirable (since if I am not
careful, then when I change the hook of one git repo, it
actually changes the hooks of all other repos too). It is easy
enough for me to work around this (i.e. by instead pointing my gitconfig
to use a template dir which is not a symlink), but I was
wondering weather this is a feature folks use (and for what end), or if
this is unintended behavior.

Furthermore, would a patch be welcome that either disables this
feature through an option (or perhaps permanently by just copying the
contents of the symlinked folder instead of creating individual
symlinks), or am I the only git user that was surprised by this
behavior and wanted to disable it?

- Alex

Re: git init with template dir

[Junio C Hamano]

Alex Cornejo <acornejo@gmail.com> writes:

> I was surprised to see that when using git-init, if the template folder
> is itself a symlink, then the contents of the template is NOT copied to
> the resulting git repository, but instead each individual file is
> symlinked.

Hmmm, I do not seem to be able to do this, though.

        $ ln -s $HOME/g/share/git-core/templates /var/tmp/git-template
        $ cd /var/tmp
	$ git init --template=/var/tmp/git-template new
        $ find new/.git -type l
        ... nothing ...

> For my particular use case, this is undesirable (since if I am not
> careful, then when I change the hook of one git repo, it
> actually changes the hooks of all other repos too). It is easy
> enough for me to work around this (i.e. by instead pointing my gitconfig
> to use a template dir which is not a symlink), but I was
> wondering weather this is a feature folks use (and for what end), or if
> this is unintended behavior.

That you had to predicate "this is undesireable" with "For my
particular use case" tells me that other people may want to see that
these things shared and automatically receive updates when the
originals in the temporate directory are updated, which makes it
sound like a "feature" not an "unintended behaviour", at least to
me.

Re: git init with template dir

[Alex Cornejo]

Junio C Hamano <gitster <at> pobox.com> writes:

> Hmmm, I do not seem to be able to do this, though.
> 
>         $ ln -s $HOME/g/share/git-core/templates /var/tmp/git-template
>         $ cd /var/tmp
> 	$ git init --template=/var/tmp/git-template new
>         $ find new/.git -type l
>         ... nothing ...

Thanks for your prompt response Juno.

That make sense. The fact that you were unable to reproduce this tells
me that there is probably something fishy/unexpected with the
environment in which I tried this (which is not too surprising, given
that I was doing it inside a linux container, inside a virtual machine,
where both of these were setup using a scripts which ultimately failed
after the git init step, due to the symlink behavior I described, but
most likely this is my own fault). I should have tried to reproduce this
on a clean slate before posting this question.

Thanks again,

Alex

Re: git init with template dir

[Junio C Hamano]

Alex Cornejo <acornejo@gmail.com> writes:

> Junio C Hamano <gitster <at> pobox.com> writes:
>
>> Hmmm, I do not seem to be able to do this, though.
>> 
>>         $ ln -s $HOME/g/share/git-core/templates /var/tmp/git-template
>>         $ cd /var/tmp
>>         $ git init --template=/var/tmp/git-template new
>>         $ find new/.git -type l
>>         ... nothing ...
>
> Thanks for your prompt response Juno.
>
> That make sense. The fact that you were unable to reproduce this tells
> me that there is probably something fishy/unexpected with the
> environment in which I tried this (which is not too surprising, given
> that I was doing it inside a linux container, inside a virtual machine,
> where both of these were setup using a scripts which ultimately failed
> after the git init step, due to the symlink behavior I described, but
> most likely this is my own fault).

I wouldn't call that your "fault".  After all, as more people want
to run Git in different environments, we would want to make sure Git
runs correctly for them.

I quickly re-scanned what we do inside "git init" and how we
populate the repository from templates.  This happens all in
builtin/init-db.c:

 - copy_templates() does opendir(), so it should not have mattered
   that I used /var/tmp/git-template that is a symbolic link to a
   real location in my quick reproduction attempt;

 - it calls a recursive copy_templates_1() with that directory
   handle it opened for the template directory.  Each entry it finds
   are inspected and

   - real directories are recursed into;
   - files are copied; and
   - symlinks are recreated.

So if I instead made a new directory /var/tmp/git-template/ and then
populated it with a bunch of symbolic links e.g. hooks, description,
etc., that points at their real location, I would have seen that the
resulting repository populated with symbolic links.

And I think that is an expected behaviour.

But if "git init" made bunch of symbolic links only because it was
given a symbolic link to the real directory via its --template
parameter, that _is_ unexpected, and we may want to dig deeper to
correct it.